Monitoring the condition of production tubing, different casing strings, joints, collars, filters, packers and perforations is crucial in oil and gas field operations. Electromagnetic (EM) techniques are common means to evaluate these components. EM sensing provides continuous, in situ measurements of the integrity of tubing/casing. EM technologies developed for such monitoring applications can be categorized into two groups: frequency-domain techniques and time-domain techniques. In frequency-domain techniques, typically, measurements are performed over a range of frequencies, low frequency and a high frequency within this range, to perform characterization of the internal and external features of the casing, respectively. Proper analysis of the responses can determine metal losses with better resolutions and also improve the robustness of the characterization process to noise. The usefulness of such measurements may be related to the precision or quality of the information and the presentation of the data derived from such measurements.